Strongly Anchoring Polysulfides by Hierarchical Fe₃O₄/C₃N₄ Nanostructures for Advanced Lithium-Sulfur Batteries

Li-S batteries have attracted considerable interest as next-generation energy storage devices owing to high energy density and the natural abundance of sulfur. However, the practical applications of Li-S batteries are hampered by the shuttle effect of soluble lithium polysulfides (LPS), which results in low cycle stability. Herein, a functional interlayer has been developed to efficiently regulate the LPS and enhance the sulfur utilization using hierarchical nanostructure of C₃N₄ (t-C₃N₄) embedded with Fe₃O₄ nanospheres. t-C₃N₄ exhibits high surface area and strong anchoring of LPS, and the Fe₃O₄/t-C₃N₄ accelerates the anchoring of LPS and improves the electronic pathways. The combination of these materials leads to remarkable battery performance with 400% improvement in a specific capacity and a low capacity decay per cycle of 0.02% at 2 C over 1000 cycles, and stable cycling at 6.4 mg cm^-2 for high-sulfur-loading cathode.